According to prior art systems, data synchronization is accomplished by first recovering a clock signal from a received data stream, and then comparing the clock signal with the incoming data. The difference in phase and frequency between the recovered clock signal and incoming data is used to correct the clock signal and thereby synchronize the data signal. In the prior art methodology, several clock cycles must elapse before a phase error of zero degrees is achieved. Thus, synchronization of data is never achieved on the first bit since by definition at least one bit must be compared to the recovered clock signal before synchronization may occur. Hence, prior art systems require the use of numerous bits as a preamble to achieve synchronization. In some instances, the preamble may be as high as 101 bits.
In the prior art systems, a sliding correlator is used for correlation of data, while for spread spectrum data, high speed microprocessors are used to achieve high chip rates.